One type of cornice lighting fixture for public transit vehicles is disclosed by U.S. Pat. Nos. 3,210,875; 3,211,904; and Des.201,380. The type of lighting fixture disclosed by these patents includes a metal housing for mounting one or more fluorescent tubes and a light transmitting panel that covers the fluorescent tubes. Spaced lens sections of the light transmitting panel are extruded from clear plastic to define triangular prisms for directing light from the fixture for general illumination and reading light. An intermediate section of the light transmitting panel is extruded from translucent plastic and extends between the spaced lens sections. Advertising signs may be mounted on the intermediate section and may either be opaque so that the indicia on the sign is lighted from the front or may be translucent so as to be back-lighted by the light shining through the translucent intermediate section.
Another type of cornice lighting fixture designed for use with public transit vehicles includes a metal housing for supporting one or more fluorescent tubes and an extruded light cover of all translucent plastic through which the fluorescent tubes provide diffused light. An advertising sign can also be carried by the translucent cover of this type of fixture so that the sign is lighted by the general illumination within the vehicle if it is opaque or is lighted by light shining through the cover if the sign is translucent. Light is diffused by all portions of this type of lighting fixture rather than being directed by lens sections as disclosed by the aforementioned patents.
Both types of cornice lighting fixtures discussed above have been utilized such that the metal housings thereof partially define an air duct upon mounting so the duct can carry either heated or cooled air for appropriately controlling the temperature within the associated transit vehicle. Such housings must be generally imperforate so that dust or other accumulation that is carried with the heated or cooled air does not collect on the plastic cover through which light shines into the interior of the vehicle.
Whatever the type of lighting fixture utilized with public transit vehicles, the cost of the fixture is a very important consideration in view of the financial condition of most public transit systems.